Make Logger instance final as SL4J suggests
diff --git a/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoLinkServiceImpl.java b/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoLinkServiceImpl.java
index e810646..b692e8e 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoLinkServiceImpl.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoLinkServiceImpl.java
@@ -18,7 +18,7 @@
 public class TopoLinkServiceImpl implements ITopoLinkService {
 	
 	protected GraphDBOperation op;
-	protected static Logger log = LoggerFactory.getLogger(TopoLinkServiceImpl.class);
+	protected final static Logger log = LoggerFactory.getLogger(TopoLinkServiceImpl.class);
 
 	public void finalize() {
 		close();